Streptococcal Infections MCQ Quiz | Respiratory Infections

Q1. The most common bacterial cause of acute pharyngitis, particularly in children aged 5-15 years, is:

Q2. The M protein of Streptococcus pyogenes is a major virulence factor primarily due to its:

Q3. The characteristic “sandpaper” rash and “strawberry tongue” seen in scarlet fever are caused by:

Q4. A 10-year-old presents with a sore throat, fever, and palatal petechiae. A Rapid Antigen Detection Test (RADT) for Group A Streptococcus is negative. What is the most appropriate next step in management?

Q5. Which of the following is a non-suppurative sequela that can follow a Streptococcus pyogenes pharyngeal infection but not typically a skin infection?

Q6. In the laboratory, Streptococcus pyogenes (Group A) is typically characterized by which combination of properties?

Q7. The most common pattern of pneumonia caused by Streptococcus pneumoniae in healthy adults is:

Q8. The primary virulence factor of Streptococcus pneumoniae that is antiphagocytic and the target of current vaccines is its:

Q9. Which diagnostic test, detecting a C-polysaccharide cell wall component, is highly specific for Streptococcus pneumoniae infection and can be performed on a urine sample?

Q10. Streptococcus pneumoniae is distinguished from other alpha-hemolytic streptococci (viridans group) by its susceptibility to:

Q11. Which of the following conditions most significantly increases the risk for invasive pneumococcal disease due to impaired clearance of encapsulated organisms?

Q12. The pneumococcal conjugate vaccine (e.g., PCV13, PCV15) is highly effective in infants and young children primarily because it:

Q13. A peritonsillar abscess (quinsy) is a deep-neck suppurative complication most commonly associated with an infection by:

Q14. The drug of choice for treating streptococcal pharyngitis to prevent acute rheumatic fever is:

Q15. The pathogenesis of acute rheumatic fever following a GAS pharyngitis is believed to be due to:

Q16. A patient with community-acquired pneumonia presents with a sudden onset of a single rigor (shaking chill) and rust-colored sputum. The most likely causative organism is:

Q17. The modified Jones criteria are used for the clinical diagnosis of:

Q18. An important difference between Post-streptococcal glomerulonephritis (PSGN) and Acute Rheumatic Fever (ARF) is that PSGN can follow:

Q19. Viridans group streptococci are normal flora of the oropharynx and are most commonly associated with which of the following conditions after entering the bloodstream?

Q20. An elevated anti-streptolysin O (ASO) titer is a useful laboratory marker for confirming a recent infection with:

Q21. The erythrogenic toxins (SpeA, B, C) responsible for the scarlet fever rash act as:

Q22. A primary advantage of the Pneumococcal Polysaccharide Vaccine (PPSV23) over the conjugate vaccine (PCV) for use in older adults is that it:

Q23. On Gram stain, streptococci characteristically appear as:

Q24. A rapid, simple, and crucial biochemical test used to differentiate Streptococci from Staphylococci is the:

Q25. Which streptococcal species is characterized by a narrow zone of beta-hemolysis and is CAMP test positive, primarily known for causing neonatal sepsis but can cause pneumonia in immunocompromised adults?